The long term objective of this research program is to improve the care of patients harboring unruptured, intracranial aneurysms. These aneurysms, present in approximately 2% of the population and being diagnosed with increasing frequency because of widespread use of MRI and CT scanning, may undergo spontaneous rupture with devastating consequences. Once discovered, however, the decision to treat must balance the risk of spontaneous rupture against the treatment risk. The annual risk of aneurysm rupture is low, but there are relatively few high quality studies documenting precise rates of rupture. Furthermore, even with the most advanced treatment techniques, one in twenty patients will suffer from neurologic morbidity from the therapy itself. Unfortunately, clinical and autopsy data that might clarify these uncertainties remain elusive. In an attempt to improve outcomes in these patients, numerous groups are exploring the predictive value of surrogate markers of rupture risk and treatment outcome. These approaches include detailed analysis of geometric and other features to be used in computational modeling for prediction of rupture risk as well as the development of innovative, minimally invasive therapies. Animal models of saccular aneurysms serve as bridge between these research hypotheses and the clinic, translating new ideas to clinical implementation. The proposed work will first confirm that the animal model accurately mimics the pathology, biology, and mechanical structure of actual human aneurysm tissue. This project will benefit patients suffering from intracranial aneurysms, both before and after treatment, with the long term goal of diminishing or eradicating the risk of devastating aneurysm rupture.